The proposed research investigates children's ability to use personal information, indicative of individual differences, to predict and explain the emotional reactions of other people. The research is based on a proposed three-stage model for the use of personal information: stage 1 involves determining whether the use of personal information is called for; stage 2 involves obtaining the necessary personal information; and stage 3 involves combining the personal information with other information to infer another person's emotion. Part I of the proposed research examines children's ability to use various forms of personal "past history" information to understand another person's atypical emotional reaction to an event. Children in kindergarten, second grade, and fifth grade are asked to predict and/or explain the emotional reactions of story characters, given information about the character's past history, information about an emotion-evoking event, or both types of information. The verbally presented stories are constructed so that the protagonist's past history changes his or her most likely emotional reaction to the subsequent event. An experiment is also included which examines the relationship of these abilities to children's cognitive capacity and social competence. Part II of the proposed research examines children's awareness of the need for personal information and their ability to seek necessary personal information. Children are asked to predict the emotional reactions of story characters, when the story situations are ambiguous with respect to their emotional implications. The children can indicate their awareness that different people might have different reactions to the same situation by making two choices of emotion or by asking the experimenter a question before predicting the story character's emotional response. The series of studies proposed tests specific hypotheses based on a social and cognitive developmental view of how children acquire the skills necessary to make affective inferences via the three-stage process described above.